The Diversity Index is a scale of 0 to 100 that represents the likelyhood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
| County | Diversity Index | |
|---|---|---|
| 1. | Suffolk County | 79.3 |
| 2. | Hampden County | 68.8 |
| 3. | Essex County | 63.4 |
| 4. | Middlesex County | 52.9 |
| 5. | Nantucket County | 50.8 |
| 6. | Worcester County | 49.0 |
| 7. | Norfolk County | 47.1 |
| 8. | Bristol County | 41.0 |
| 9. | Plymouth County | 38.4 |
| 10. | Hampshire County | 34.1 |
| 11. | Dukes County | 32.6 |
| 12. | Berkshire County | 27.8 |
| 13. | Barnstable County | 24.5 |
| 14. | Franklin County | 22.1 |
